1. The purpose of the present study was to examine whether zymosan, which is a component of fungi, affects feed passage through the digestive tract in chicks (Gallus gallus). 2. Intraperitoneal (IP) injection of 2.5 mg zymosan significantly reduced the crop-emptying rate and this effect was similar to that of 100 µg lipopolysaccharide (LPS). Zymosan affected phenol red transit from the proventriculus. 3. Zymosan significantly affected the gene expression of interleukin-1β (IL-1β), IL-6, IL-8 and histidine decarboxylase in various regions of the digestive tract. 4. The present study suggested that zymosan retarded feed passage through the digestive tract in chick and interleukins and histamine may be participating in this process.